Positive HPT and negative doctors test


So for the past three days I’ve done a HPT and been getting faint lines. Today I took a digital clear blue test and got a positive. However I went to the doctor and did a urine test and they told me it was negative. I went in to another clinic because I was so confused as to why I got positive at home and negative at the doctors office. There they told me it was negative again, but there I was able to see a faint line again. I’m so confused...anyone has experienced something similar?? I’m so confused 😭